Multidrug resistance among gram-negative pathogens that caused healthcare-associated infections reported to the National Healthcare Safety Network, 2006-2008.

We evaluated isolates of Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii that were reported to the National Healthcare Safety Network from January 2006 through December 2008 to determine the proportion that represented multidrug-resistant phenotypes. The pooled mean percentage of resistance varied by the definition used; however, multidrug resistance was relatively common and widespread.